1. Field of the Invention
This invention relates to the field of industrial machines such as forklift trucks, and more particularly to an occupant safety seat assembly for protecting the operator.
2. Description of the Prior Art
While extensive research has been done in the field of restraining means for protecting consumer motor vehicle operators, the problem has been to find a suitable device for industrial machines that will be accepted and used by the operator without overly restricting his ingress and egress, visibility, and upper body movement, all critical for safe operation, especially for the factory and warehouse uses of lift trucks employing an overhead guard. For years, seat belts have been proposed. Lap belts, shoulder harnesses, and three point automotive-type belts have the chief disadvantage, for a typical lift truck where the width is narrow and the seat is offset to one side of the truck centerline, that the upper body of the operator can still be thrust to one side by lateral forces, in spite of the belt, possibly causing injury to the operator who comes into contact with an object, or the truck itself.
Side screens or doors on the overhead guard would contain the operator, but are easily defeated or removed, and often prove detrimental because new hazards are created due to the possibility of underside impact with the head/overhead guard and reduced visibility. Loads are not properly spotted, or factory workers not seen in time, resulting in injury to bystanders from falling boxes or to pedestrians run down in plant aisles.
In cases of misuse, the truck may tip upon two wheels or, when operated carelessly, even upset, and unless restrained inside the overhead guard, the operator is subject to injury. The hazard then is likely to be the overhead guard itself. But operation of the lift truck without its overhead guard, to avoid injury to the few careless operators who misuse the truck, would expose the many careful operators to far greater hazards from falling loads in their normal work environments; thus, no safety standard calls for seat belts or side screens, but the overhead guard is required by all safety codes applicable to lift trucks except in strictly defined, low lift uses. There remains the problem, then, that no acceptable safety seat arrangement has heretofore been invented for use with an overhead guard on industrial machines, such as forklift trucks.